Add deno environment support

Author: nazarhussain

vitest.base.unit.config.ts

@@ -1,6 +1,29 @@
 import path from "node:path";
 import {defineConfig} from "vitest/config";
+import {BuiltinEnvironment} from "vitest/node";
+import {Environment} from "vitest/environments";
 const __dirname = new URL(".", import.meta.url).pathname;
+import denoEnvironment from "./vitest/environments/deno";
+
+function getTestEnvironment(
+  runtime?: string
+): BuiltinEnvironment | Environment {
+  switch (runtime) {
+    case "deno":
+      return denoEnvironment;
+    case "node":
+      return "node";
+    default: {
+      if (runtime) {
+        throw new Error(`Unsupported JS Runtime '${runtime}'`);
+      } else {
+        throw new Error(
+          "Please define `JS_RUNTIME` env variable to either node | deno"
+        );
+      }
+    }
+  }
+}
 
 export default defineConfig({
   test: {
@@ -23,5 +46,6 @@ export default defineConfig({
           "hanging-process",
         ],
     onConsoleLog: () => !process.env.TEST_QUIET_CONSOLE,
+    environment: getTestEnvironment(process.env.JS_RUNTIME),
   },
 });

vitest/environments/deno.ts

@@ -0,0 +1,32 @@
+import type {Environment} from "vitest/environments";
+
+export default <Environment>{
+  name: "deno",
+  transformMode: "ssr",
+  async setupVM() {
+    // @ts-expect-error - Ignore the global object
+    if (!global.Deno) {
+      throw new Error("Not valid deno runtime available");
+    }
+
+    // Deno supports `node:vm` module.
+    const vm = await import("node:vm");
+    const context = vm.createContext();
+    return {
+      getVmContext() {
+        return context;
+      },
+      teardown() {
+        // called after all tests with this env have been run
+      },
+    };
+  },
+  setup() {
+    // custom setup
+    return {
+      teardown() {
+        // called after all tests with this env have been run
+      },
+    };
+  },
+};